Zephyr's Kconfig symbols and defaults for SDHC/SDMMC disk drivers and
the disk access subsystem were reworked between Zephyr v2.5.0 and
v2.6.0. Update MicroPython accordingly.
Signed-off-by: Maureen Helm <maureen.helm@nxp.com>
The zephyr build system supports merging application-level board
configurations, so there is no need to reproduce this functionality in
MicroPython.
If CONF_FILE is not explicitly set, then the zephyr build system looks for
prj.conf in the application directory. Therefore we rename the MicroPython
prj_base.conf to prj.conf.
Furthermore, if the zephyr build system finds boards/$(BOARD).conf in the
application directory, it merges that configuration with prj.conf.
Therefore we rename all the MicroPython board .conf files and move them
into a boards/ directory.
The minimal configuration, prj_minimal.conf, is left in the application
directory because it is used as an explicitly set CONF_FILE in
make-minimal.
